Metathesis reactions are widely used in chemical syntheses, e.g. in the form of ring-closing methatheses (RCM), cross metatheses (CM), ring-opening metatheses (ROM), ring-opening metathesis polymerizations (ROMP), cyclic diene metathesis polymerizations (ADMET), self-metathesis, reaction of alkenes with alkynes (enyne reactions), polymerization of alkynes and olefinization of carbonyls (WO-A-97/06185 and Platinum Metals Rev., 2005, 49(3), 123-137). Metathesis reactions are employed, for example, for the synthesis of olefins, for ring-opening polymerization of norbornene derivatives, for the depolymerization of unsaturated polymers and for the synthesis of telechelic polymers.
In known metal-carbene complexes, the carbene radical has a wide variety of structures. WO-A-96/04289 and WO-A-97/06185 disclose, for example, metathesis catalysts having the following in-principle structure:
where M is osmium or ruthenium, R and R1 are organic radicals having a wide range of structures, X and X1 are anionic ligands and L and L1 are uncharged electron donors. In the literature, the customary term “anionic ligands” in such metathesis catalysts refer to ligands which, when viewed separately from the metal centre, are negatively charged for a closed electron shell.
One specific representative of this class of compounds is the compound known as “Grubbs (I) catalyst”:

Furthermore, WO-A-00/71554 discloses a group of catalysts which are referred to in the art as “Grubbs (II) catalysts”.

US 2002/0107138 A1 discloses further metathesis catalysts of the type depicted below, which are also referred to in the literature as “Hoveyda catalyst”.

WO-A-2004/035596 discloses further metathesis catalysts of the type depicted below, which are also referred to in the literature as “Grela catalyst”.

Furthermore, WO-A-03/011455 discloses hexacoordinated complex catalysts which are known under the name “Grubbs (III) catalysts”.

In addition, catalysts in which the two substituents located on the carbon atom of the carbene radical are bridged are known.

According to Fürstner et al. (Chem. Eur. J. 2001, 7, No 22, 4811-4820), the first representative of the abovementioned class of compounds were prepared by Hill et al. (K. J. Harlow, A. F. Hill, J. D. E. T. Wilton-Ely, J. Chem. Soc. Dalton Trans. 1999, 285-291), who initially assigned an inappropriate structure to the reaction product. The correct structure was assigned by Fürstner et al. (J. Org. Chem. 1999, 64, 8275-8280). This catalyst is that referred to above as Hill-Fürstner catalyst. Derivatives of this catalyst which contain an NHC ligand in place of the phosphine ligand were described by Nolan in WO-A-00/15339. These derivatives described by Nolan are also suitable as starting material for the synthesis of further ruthenium-carbene complexes by cross metathesis (WO-A-2004/112951)
US-A-2003/0100776 describes, on page 8, paragraph [0087], catalysts which have a carbene ligand in which the radicals R1 and R2 are bridged, with the resulting cyclic group being able to be aliphatic or aromatic and contain substituents or heteroatoms. It is stated that this cyclic group typically has from 4 to 12, preferably from 5 to 8, ring atoms. Explicit examples of such cyclic groups are not described or made obvious.
Other catalysts in which the two substituents located on the carbon atom of the carbene radical are bridged are not known at present.
WO-A-97/06185 describes, on page 7, lines 39-40, an unsuccessful attempt by Grubbs to react RuCl2(═CHR)(PPh3)2 with 9-diazafluorene. He states that “however, no reaction was observed with diphenyldiazomethane or 9-diazafluorene at RT”.

Owing to the many possible uses, there continues to be a great demand for new catalysts for metathesis reactions.
According to the present invention, it has surprisingly been found that novel transition metal complex catalysts which have a fluorenyl ligand and can be used as catalysts for metathesis reactions can be synthesized when specific reaction parameters are adhered to.